The invention relates to a device for centring, during operation, a disk to be read or recorded while rotating. The device comprises a turntable which, during operation, can be rotated about an axis of rotation and a number of centring parts which are connected to the turntable. In the operating condition of the disk, the parts are situated at least partly in the central disk hole and can be swung against the resilience with their free ends in the direction of the axis of rotation about a pivot extending at least substantially tangentially with respect to a circle situated concentrically about the axis of rotation.
Such a device is disclosed in U.S. Pat. No. 4,218,065 (herewith incorporated by reference). As explained therein it is necessary in devices for optically reading or optically writing a disk to accommodate the disk in a position which is correct as accurately as possible both for writing and reading and both in the axial and radial directions. In order to obtain a good accommodation in the radial direction, centring parts are each connected with one end to a supporting member in such a manner that the free ends thereof can be swung independently of each other against resilient action in the direction of the axis of rotation. In itself this construction is satisfactory but if a force in the plane of the disk is exerted on the disk placed on the turntable, as a result of which it is moved in a position which is eccentric with respect to the axis of rotation, some of the centring parts will be swung with their free ends in the direction of the axis of rotation, while further centring parts situated approximately diametrically opposite to said centring parts will tend to swing in a direction away from the axis of rotation under the influence of the resilient force. When the force is removed it may occur that, as a result of the occurring friction between the centring parts and the edge of the disk hole, the disk can be forced back by the centring parts into the position which is not accurately concentric with respect to the axis of rotation and hence the disk will remain in a position which is slightly eccentric with respect to the axis of rotation.